Thermostatic element



April 14, 1953 Filed NOV. 20, 1950 R. L. PERL THERMOSTATIC ELEMENT 2SHEETS- SHEET l April 14, 1953 F@L L PERL 2,635,003

THERMOSTATIC ELEMENT Filed Nov. 20, 1950 2 SHEETSSHEET 2 JNVENTOR. i? zCha/'Q7 A Per! BZ@- HJM@ Patented Apr. 14, 1953 UNITED STATELS PATENTOFFlCE THERMOSTATIC ELEMENT Richard L. Perl, Galion, Ohio, assignor toThe Tappan Stove Company, Mansfield, Ohio, a

corporation of Ohio 6 Claims. 1

This invention relates to improvements in thermostatic elements oi themonometallic type.

Thermostatic elements of this type have a large number of uses but areespecially adapted for use in ignition and control systems for thegaseous fuel burners of cooking ranges which einploy a gaseous fuelpilot burner by which the main burners are ignited and/ or controlled.In systems of this character the llame from the pilot burner impinges onthe thermostatic element and causes it to operate a valve, an electricswitch or other shiftable element. Consequently it is necessary toprovide a thermostatic element which is not affected by the ambienttemperature but depends upon the application of localized heat foractuation. It is also necessary that the element be so constructed thatits life and utility will not depreciate ydue to the constantapplication of a name thereto.

The embodiment of the invention disclosed herein is a one piece sheetmetal stamping having two legs disposed at right angles to each otherwhich are rigidly secured to iixed supports, and an outwardly extendingarm the free end of which is adapted to be operatively connected to ashiftable control member.

In the drawings the invention is illustrated in connection with anautomatic ignition system for a pair of spaced top burners of a cookingrange. A gaseous fuel pilot burner is disposed between the main burners.It is ignited by an electric ignition element and the main burners areignited by the pilot burner through ila-sh tubes which extend from themain burners into close proximity with the pilot burner. The supply ofgas to the pilot burner is controlled by the valves for the main burner.The opening of any of the main burner valves to supply gas to a mainburner will also admit gas to the pilot burner. The electric ignitionelement is in an electric circuit which includes a normally closedswitch and a plurality of normally open switches. There is a normallyopen switch operatively associated with each burner valve in such amanner that the opening of the valve will close the switch, andconversely the closing of' the valve will open the switch. The normallyclosed switch is arranged to `be opened by a thermostatic element whichis mounted in position to be heated by the pilot burner after it hasbeen ignited by the electricl ignition element. The opening of thenormally closed switch will break the circuit to and (ie-energize theelectric ignition element which need not be energized after the pilotburner has been ignited. In operation it is only necessary to open theselected burner valve. The opening of the valve admits gas to the mainburner and to the pilot burner and closes the normally open switchassociated therewith. The closing of the normally open switch will makethe circuit to and energize the electric resistance element which willthen ignite the 4pilot burner. The pilot burner will ignite the mainburner through its flash tube, and will heat the thermostatic element,and the thermostatic element when heated will open the normally closedswitch and break the circuit to and de-energize the electric resistanceelement. In the event the pilot burner should be extinguished for anyreason while the gas is still turned on the thermostatic element willcool and close the normally closed switch which will re-energize theelectric resistance element and re-ignite the pilot burner.

One of the objects of theinvention is to provide a thermostatic elementwhich may be quickly, easily and inexpensively formed from regular stocksheet metal.

Another object of the invention is to provide thermostatic element ofthis type in which the life and utility thereof will not depreciate dueto the constant application of a flame thereto.

Other and more limited objects of the invention will be apparent fromthe. following specification and the accompanying drawings forming apart thereof in which:

Fig. l is a diagrammatic layout showing my improved thermostatic elementincorporated in an automatic ignition system for the top burners of acooking range;

Fig. 2 is an enlarged top plan View ofthe removable control unit;

Fig. 3 is a longitudinal section taken on the line 'fl-3 of Fig. 2; and

Fig. 4 is a transverse section taken on the line 4-6 of Fig. 2.

Referring now to the drawings by reference characters, the numerals land 2 are applied to a pair of spaced top burners of' a cooking range.Gaseous fuel is supplied to the burner l, from a supply manifold 3,through its mixing tube 4; and to the burner 2, from the manifold 3,through its mixing tube 5. A pair of cutoff valves il and 'l control thesupply of gas to the burners l and 2, respectively. A pilot burner 3 issuitably mounted between the free ends of a pair of aligned flash tubes9 and lll which are carried by the burners l and 2, respectively.Gaseous fuel is supplied to the pilot burner 8 from the manifold 3through the valve l and the conduit il or through the valve and theconduits i2 and il. The cut-off valves B and 'I are so constructed thatwhen either one is turned on to supply gas to one of the main burners land 2 gas is also supplied to the pilot burner B. rlhe pilot burner 8 isignited by an electric resistance ignition element I3 when it isenergized, and the main burners I and 2 are ignited by the pilot burner8 through the flash tubes 9 and I5. The electric ignition element I3 ismounted in operative relation to the pilot burner 8 on an insulatingblock It of a removable control unit generally indicated by the numeralI5. The energization of the electric ignition element I3 is controlledby a pair of normally open switches I5 and Il and a normally closedswitch I8. The normally closed switch I is operatively associated withthe valve 6 and comprises, the contacts I8 and 28 and the bridgingconductor bar 2 I. The switch I6 is adapted to be closed through themedium of a cam section 22 carried by the valve stem 23 of the valve 6and a link 2li simultaneously with the opening of the valve 8 and to beopened simultaneously with the closing of the Valve 5. The normally openswitch I 'I is operatively associated with the valve 'I and comprisesthe contacts 25 and 25 and the bridging conductor bar 21. It is adaptedto be closed through the medium of a cam section 28 carried by the Valvestem 29 of the Valve 'I and a link 3!) simultaneously with the openingof the Valve I and to be opened simultaneously with the closing of thevalve The switch I8 is incorporated in the control unit I5 and isadapted to be opened by a thermostatic element 3l which is alsoincorporated in the control unit I5 in position to be heated by theflame from the pilot burner 8. The specific construction of the controlunit I5 and the component parts thereof will be described in detailhereinafter.

In operation it is only necessary to turn on the control valve of theselected main burner. The turning on or opening of the valve will closethe associated normally open switch I6 or Il and supply gas to both themain burner and the pilot burner. The closing of the switch I5 or il'will make the circuit to and energize the electric ignition element I3which will then ignite the pilot burner. The main burner will then beignited through the flash tube by the pilot burner. f

After ignition the pilot burner will also heat the thermostatic element3| which after being heated will open the normally closed swtich I8 andmaintain it open as long as the thermostatic element 3| is heated by thepilot burner. of the normally closed switch i8 breaks the circuit to andde-energizes the electric ignition element I3 which need not remainenergized after the pilot burner has been ignited. If after one mainburner has been ignited the other main i burner is turned on it will beignited through its flash tube by the pilot burner which has alreadybeen ignited, it being understood that the pilot burner is arranged toburn as long as either of the main burners is turned on. If the pilotburner should be extinguished for any reason while either of the mainburners is turned on the thermostatic element SI will immediately cooland allow the switch I8 to close which will reestablish the circuit toand re-energize the electric ignition element I3 which will thenreignite the pilot burner 8.

The electric circuit which includes the electric ignition element I3,the normally open switches I 6 and I'I and the normally closed switch I8will now be traced, assuming first that the burner I is turned on byopening the valve 6. The opening of the valve 6 will supply gas to themain burner I and the pilot burner 8 and will close the normally openswitch I6. As soon as The opening the switch I6 is closed current willflow from one side 32 of the line through the leads 33 and 34 to theContact I 9 of the switch I5 and through the bar 2l to the contact 28.From the contact 25 the current will flow through the lead 35 to theterminal 38 of the electric resistance ignition element I3 and thenthrough the ignition element I3 to the terminal 3l thereof. From theterminal 3l the current will flow through the lead 38 to the normallyclosed switch I8, thence through the switch I8 and back to the otherside 39 oi the line through the lead 45, completing the circuit to andenergizing the ignition element I3, which will remain energized untilthe thermostatic element opens the switch I8 and breaks the circuit.Assuming that the main burner 2 is first turned on by opening the valve'I, the opening of the valve I will supply gas to the main burner 2 andthe pilot burner 8 and close the normally open switch il. As soon as theswitch I'I is closed current will iiow from the side 32 of the linethrough the lead 33, switch I'I and lead "il to the lead 35. From thelead the current will flow through the ignition element I3, switch I8and back to the other side 39 of the line as previously described. Theturning on of either one of the main burners after the other main burnerhas been turned on and ignited along with the pilot burner will notenergize the electric ignition element I3 as the circuit thereto cannotbe completed since the thermostatic element 3i is holding the switch I8open.

The removable control unit I5 includes a frame 50, the electric ignitionelement i3 and the insulation block Ill, the normally closed switch I8,and the thermostatic element SI. The frame 55 is formed of thin sheetmetal and comprises a base 5I having a pair of spaced parallel upwardlyextending vertical side walls 52 and 53 formed integrally therewith. Theinner ends of the side walls 52 and 53 are connected by a vertical endwall 55, and the upper edges of the side walls 52 and 53 are connectedby a transverse brace 55 which is disposed rearwardly of the end wall54. The base 5I is cut away or apertured adjacent the end wall 54 asindicated at 56 and the side walls 52 and 53 are notched opposite thecut away section of the base as shown at 58. The other end of the base5I eX- tends beyond the free ends of the side walls 52 and 53 andterminates in a downward step 5S which is removably mounted in a slot 6Bin a xed supporting member SI. The opposite end of the frame 55 rests onthe ash tubes 9 and I5 with the flash tubes 9 and Iii engaging thenotched portions 58 of the side walls 52 and 53. When in position thecut away section 56 of the frame base 5I is disposed over the pilotburner 3 so that when it is ignited it will project a flame up betweenthe side walls 52 and 53. The electric resistance ignition element I3 isremovably secured between the terminals 36 and 31 carried by the blockI5 of insulating material. The block I5 is mounted between the sidewalls 52 and 53 adjacent the transverse brace 55 in position to maintainthe ignition element I3 in operative relation to the pilot burner 8.

The normally closed switch I8 is secured to the base 5I between the sidewalls 52 and 53 a short distance inwardly from the step 58 and comprisesa stationary Contact 62 and a movable contact 63. The stationary contact62 is adjustably mounted in a sleeve B5 which is mounted in a, plate 65of insulating material beneath an aperture 66 in the base 5I. The plate65 is secured to the under side of the base 5| by rivets 67 and SS. Themovable contact 53 is secured to the under side ef the top section 99 ofa U- shaped spring member which normally biases the Contact 63 intoengagement with the stationary Contact 62. The bottom section 79 of thespring member is secured to the upper side oi the base 5l by the rivets61.

The thermostatic element 3| is formed from a single piece of sheet metaland comprises a vertical leg 76, a horizontal leg 'H and an arm 72. Theupper end or the vertical leg 70 is welded to the Linder side or thetransverse brace 55 at 73. The horizontal leg l! extends outwardly fromthe lower end of the Vertical leg 'i6 across the cut away section 56 ofthe base 5i above the pilot burner 8 in position to be heated therebyand has its free end welded to the end wall 54 at 74. The arm 'i2extends outwardly from the vertical leg 79 opposite the horizontal legli. The side walls of the legs 'I0 and 1i and the arm 72 are alldisposed in substantially the same plane, and the lower edge of the arm'l2 is turned at a right angle to the side thereof to provide astiiening rib 75. The free end 76 of the arm 72 is disposed under atongue 'I7 carried by the top section 69 of the U-shaped spring memberof the normally closed switch I8. After the pilot burner has beenignited by the electric ignition element I3 the pilot burner flame willimpinge on and heat the horizontal leg 'H of the thermostatic element3|. The heating of the leg 'H will elongate it which will fiex the arm72 about the weld 'I3 and cause the free end 'l1 of the arm 72 to moveupwardly and lift the contact B3 out of engagement with the stationarycontact 62.

The automatic ignition system shown and described herein in connectionwith my improved thermostatic element forms no part of the presentinvention but constitutes the subject matter of my co-pendingapplication Serial No. 196,681, led November 20, 1950.

From the foregoing it will be apparent to those skilled in this art thatI have provided a very simple and efcient mechanism for accomplishingthe objects of the invention.

It is to be understood that I am not limited to the specificconstruction shown and described herein as various modifications can bemade therein within the spirit of the invention.

What is claimed is:

1. A monometallic thermostatic element comprising a single imperforatepiece of sheet metal having a vertical leg, a horizontal leg extendingoutwardly from the lower end of said vertical leg, and an arm extendingoutwardly from the lower end of said vertical leg opposite saidhorizontal leg, the outer ends of said legs being rigidly secured tofixed supporting means, and the free end of said arm being adapted tooperatively engage a shiftable member and to ilex upwardly when heat isapplied to said horizontal leg.

2. A thermally responsive control unit comprising a frame having a base,a pair of spaced side walls secured to and extending upwardly from saidbase, an end wall extending between said side walls, a transverse bracespaced from said base secured to and extending between said side wallsrearwardly of said end wall, an aperture through said base adjacent saidend wall, a monometallic imperforate thermostatic element having avertical leg rigidly secured to said brace and extending downwardlytherefrom, a horizontal leg integral with said vertical leg extendingoutwardly from the lower end of said vertical leg across said apertureand having the outer end thereof rigidly secured to said end wall, andan arm integral with said vertical leg and extending outwardly from thelower end thereof opposite said horizontal leg, the free end of said armbeing adapted to operatively engage a shiftable member and to iiexupwardly when neat is applied to said horizontal leg.

3. A thermally responsive control unit comprising a frame and amonornetallic imperforate thermostatic element carried by said frame,said thermes-tatie element being formed from a single piece of sheetmetal and comprising a vertical leg having the upper end thereof rigidlysecured to said frame, a horizontal leg extending outwardly from thelower end oi said vertical leg and having the outer end thereof rigidlysecured to said frame, and an arm extending outwardly from the lower endof said vertical leg opposite said horizontal leg, the free end of saidarm being arranged to operatively engage a shiftable member and to flexupwardly when heat is applied to said horizontal arm.

4. A monometallic thermostatic element comprising a single imperforatepiece of sheet metal having a vertical leg, a horizontal leg extendingoutwardly from the lower end of said vertical leg, and an arm extendingoutwardly from the lower end of said vertical leg opposite saidhorizontal leg and having the lower edge thereof turned at an angle tothe side thereof to provide a stiiiening rib, the outer ends of saidlegs being rigidly secured to xed supporting means, and the free end ofsaid arm being adapted to operatively engage a shiitable member and toflex upwardly when heat is applied to said horizontal leg.

5. A monometallic thermostatic element comprising a single imperforatepiece of sheet metal having a vertical leg, a horizontal leg extendingoutwardly from the lower end of said vertical leg, and an arm extendingoutwardly from the lower end oi' said vertical leg opposite saidhorizontal leg, the sides of said legs and said arm being disposedsubstantailly in the same plane, the outer ends of said legs beingrigidly secured te xed supporting means, and the free end of said armbeing adapted to operatively engage a shiftable member and to flexupwardly when heat is applied to said horizontal leg.

6. A monometallic thermostatic element comprising a single imperforatepiece of sheet metal having a vertical leg, a horizontal leg extendingoutwardly from the lower end of said vertical leg, and an arm extendingoutwardly from the lower end of said vertical leg opposite saidhorizontal leg with the lower edge thereof turned at an angle to theside thereof` to provide a stilening rib, the sides of said legs andsaid arm being disposed in substantially the same plane, the outer endsof said legs being rigidly secured to fixed supporting means, and thefree end of said arm being adapted to operatively engage a shiftablemember and to ex upwardly when heat is applied to said horizontal leg.

RICHARD L. PERL.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date Re. 22,688 Higley Nov. 6, 1945 2,080,385 Congdon May 11, 19372,483,939 Schickler Oct. 4, 1949 2,487,963 Cerny Nov. 15, 1949

